I recently picked up a Crumpler Haven to use for carrying my Canon 40D. I purchased the medium size with some trepadation, as their size recommendations sugges that it won’t fit anything larger than a compact SLR (Canon Rebel, Nikon D3x00). It seems that th suggestions are too conservative—my 40D fits just fine with the Canon 10-22mm or 17-55mm affixed and leaves enough room for a 50mm alongside. You can’t fit two big lenses, like the aforementioned zooms, in the bag simultaneously, but you can reverse my setup (50mm on the camera, bigger lens beside it).
The Haven has proved quite nice. It’s enough on its own to toss in the car if I don’t plan on walking much in my journey. More importantly, it fits perfectly in a GR1 beside a liter of water.